Study of the Effect of Innate on the Inflammatory Response to Endotoxin

This research study will examine the role of innate immunity on the Inflammatory response of monocytes and macrophages to endotoxin. Approximately 1450 healthy participants aged 18 years and older will be identified and recruited from the Environmental Polymorphism Registry (EPR). The EPR is a long-term project to collect and store up to 15,000 DNA samples for use in research studies from individuals in the greater North Carolina Triangle Region. It is anticipated that approximately 50% of the participants contacted will enroll and about 15% of participants enrolled will withdraw. This controlled, observational gene association study will recruit participants on the basis of genotype and then observe the phenotype of each participant. There are several SNPs of interest in the genes TIRAP, MyD88, ABCA1, CD14, CD44, ITIH3, ITIH4, TLR4, TNFa, TLR5, IRGM, and APOL1. In addition there are alleles of interest in the gene ApoE. These alleles taken together are considered a polymorphism. For each polymorphism of interest a separate group of participants will be recruited (including heterozygous and homozygous for both the minor and major alleles for each SNP). A maximum of 200 mLs of blood will be obtained from each participant during one visit lasting approximately 1-1.5 hours. Blood monocytes will be isolated from the donated blood samples and cultured to obtain macrophages. The macrophages will be exposed ex vivo to an endotoxin (LPS) and to PAM3CSK4 to determine cell response depending on genotype. In studies of APOL1, a urine specimen will also be collected to evaluate for protein filtration. The primary objective is to determine associations between select polymorphisms in genes \[TIRAP (TIR Associated Protein), MyD88 (Myeloid Differentiation Primary Response Protein 88), ApoE (Apolipoprotein E), ABCA1 (ATP Binding Cassette Transporter A1), CD14, CD44, ITIH3, ITIH4, TLR4, TNFa, TLR5, IRGM, and APOL1\] and quantitative in vitro inflammatory functions of two cell types, the macrophage and neutrophil. The primary endpoints of this study for both cell types will be levels of 6 cytokines TNF alpha, IL-6, MIP-2, IL-8, MCP-1, and IFN-beta (ELISA) induced by LPS and by PAM3CSK4 plus baseline cytokine levels (no exposure to LPS or PAM3CSK4). Urinary levels of protein will be quantified in some studies as a measure of early kidney dysfunction. We hope the results of this study may lead to discovery of important information regarding the role of MDC1 (Mediator of DNA damage Checkpoint protein 1) in human disease, potentially identifying new targets for future studies.